Metallization of ceramic vacuum chambers for SNS ring injection kicker magnets

Abstract

AbstraclCeramic chambers will beused inthe pulsed kicker magnets forthe injectionof Hinto the US Spallation Neutron Source (SNS)accumulator ring. There are two reasons for using ceramic chambers in kickers: (1) to avoid shielding of a fast-changing external magnetic field by metallic chamber walls; and(2) to reduce heating due to eddy currents.The inner surfaces of the ceramic chambers will be coated with a conductive layer, possibly titanium or copper(Cu) with a titanium nitride(TiN) overlayer, to reduce the beam coupling impedance and provide passage for beam image current. This paper describes the development of sputtering method for the 0.83m long 16cm inner diameter ceramic chambers. Coatings of Ti, Cu and TiN with thicknesses up to 10~m were produced by means of DC magnetron sputtering. The difficulty of coating insulators was overcome with the introduction of an anode screen. Films with good adhesion, uniform longitudinal thickness, and conductivity were produced.

Fast-switching magnet serving a spallation-driven ultracold neutron source

“…In addition, the inductance of the magnet would transiently be reduced, increasing the rate-of-rise of current of the power supply. Therefore, alumina is frequently used for the tube in a kicker magnet [9,[24][25][26][27][28]. However, a thin metallic coating is frequently applied to the inner surface of the alumina tube to both screen the kicker magnet yoke from the beam [25- 28], and also to prevent build-up of static charge on the tube [27].…”